Problem $2(15$ pts$)$

$```$

int main$($void$)\{$

int my$\_$rank, comm$\_$sz$,$ n $=1024,$ local$\_$n;

double a $=0\mathrm{.}0,$ b $=3\mathrm{.}0,$ h$,$ local$\_$a$,$ local$\_$b;

double local$\_$int, total$\_$int;

int source;

MPI$\_$Init$($NULL$,$ NULL$)$;

MPI$\_$Comm$\_$rank$($MPI$\_$COMM$\_$WORLD, &my$\_$rank$)$;

MPI$\_$Comm$\_$size$($MPI$\_$COMM$\_$WORLD, &comm$\_$sz$)$;

h $=($b$-$a$)/$n; $/*$ h is the same for all processes $*/$

local$\_$n $=$ n$/$comm$\_$sz; $/*$ So is the number of trapezoids $*/$

local$\_$a $=$ a $+$ my$\_$rank$*$local$\_$n$*$h;

local$\_$b $=$ local$\_$a $+$ local$\_$n$*$h;

local$\_$int $=$ Trap$($local$\_$a$,$ local$\_$b$,$ local$\_$n$,$ h$)$;

if $($my$\_$rank $!=0)\{$

MPI$\_$Send$($&local$\_$int, $1,$ MPI$\_$DOUBLE, $0,0,$

MPI$\_$COMM$\_$WORLD$)$;

$```$

In parallel programs, we need to use both global variables and local variables. Given the above trapezoidal rule program in MPI. For all variables from line $2$ to $5,$ determine which are local and which are global.